Wednesday, February 18, 2015

Composite experts at the University of Sheffield Advanced Manufacturing Research Centre (AMRC) with Boeing in Rotherham, are hoping to shed some light on the technology’s "dark arts" with the help of some traditional Yorkshire skills.

Based in a dedicated extension to the AMRC Factory of the Future on the Advanced Manufacturing Park (AMP), the composites centre extends the AMRC's expertise in metals production into the new generation of carbon fibre composite materials. These composite materials are increasingly used in aerospace, marine, automotive and other high-value industries for their combination of light weight and high strength but they are often difficult to manufacture.

The Composite Centre has recently invested £150,000 in an FT Dornier Rapier Loom, especially designed to weave composites without the risk of the highly electrically conductive carbon fibres causing it to short circuit.

Using the same advanced methods of weaving fabrics and yarns, experts will be to design and weave their own material having previously been limited to using commercially available woven reinforcing materials.

The new capability means the centre will be able to push the boundaries of processes like Resin Transfer Moulding, where components are made by injecting resin into a mould into which dry fibre has been laid down.

Dr Jody Turner, who specialises in novel materials and processes at the AMRC Composits Centre (pictured, right), said: "Resin Transfer Moulding (RTM) is a bit of a "dark art." RTM is supposed to be a very rapid and highly production orientated process, but getting it right can involve trial and error. Sometimes the resin doesn't penetrate all of the material and parts of the component are left completely dry, which makes it useless.

"We plan to carry out research that will help us to understand more about what happens during RTM injection and why results can be so erratic."

Composite Centre researchers have already been studying how resin flows through fabrics made from carbon fibre and found the resin flow through the fabric isn't symmetrical, despite the weave pattern being perfectly symmetrical. They believe this may be a result of slightly differing yarn tensions within the fabric.

Now they hope to increase their knowledge by experimenting with different tensions for the warp – the long continuous threads – and the weft – the thread that is fed across the loom between the warp threads to create the woven material.

Turner added: "If we can control warp and weft tension we might be able to influence resin flow. We also want to push the machine to the limit of its capabilities. For example, it isn't designed to produce three dimensional structures, but we are hoping to create structures like pockets and flaps."

If the researchers are successful, they could be able to weave materials that could be opened up to form a series of boxes or a honeycomb structure that would give the completed composite component additional strength.